The present invention relates to supporting prostheses which are capable of growth. In particular, the present invention relates to supporting prostheses for supporting a vessel from inside as well as heart valve-carrying or blood vessel-carrying supporting prostheses which can include “tissue engineered” autologous or heterologous tissue or heart valve tissue which is foreign to the body, but which is decellularized or fixed. Such support prostheses can also be called “stents”.
Stents are widely used for supporting narrowed or damaged vessels, for example, following cardiological interventional procedures or following invasive surgical procedures. Since their introduction at the end of the seventies, stents have also been very widely used in congenital heart defects.
In treating children, for example newborns with congenital heart diseases, the size of the stents used is adapted to the size of the child's vessel. Thus, a stent implanted in the childhood years must, due to the later growth of the child, either be repeatedly stretched open by means of balloon angioplasty or must be replaced with larger stents in one or more surgical procedures in order to prevent a narrowing.
The prior art has confronted this problem in different manners. There exist stents which are composed of materials which are degradable in the body. Such biologically degradable or bio-absorbable stents can develop their support function shortly following implantation into a vessel and gradually disappear thereafter. Known degradable materials for this purpose are polymers or metals. Such bio-degradable stents are for example described in Erne et al. (2006), Cardiovasc. Intervent. Radiol. 29, 11-16.
However, biologically degradable stents imply certain disadvantages. For one, the disappearance of the stent structure also implies a loss of the support function associated therewith. This loss is a particularly severe problem especially in congenital vessel anomalies since, for one, the desired support function is insufficient and/or is only present for a short period of time, although in most cases it is needed for a long time. Moreover, inflammatory and/or foreign body reactions, in some cases severe, are observed at the vessel wall, primarily due to the dissolution of stents made of biologically degradable polymers.